diff --git a/src/agent/prompts/prober/10-probe-doctrine.md b/src/agent/prompts/prober/10-probe-doctrine.md
index f691911..b862070 100644
--- a/src/agent/prompts/prober/10-probe-doctrine.md
+++ b/src/agent/prompts/prober/10-probe-doctrine.md
@@ -23,4 +23,4 @@ Find out what he actually wants taught. With a subject he doesn't know yet, the
 
 Your questions are the substance of the session right now: they **open instantly** in the learner's dock, front and center — that immediacy is exactly what probing needs. Ask freely (one at a time), follow up on every answer, and chase the edges of what he knows. The probe is working when the questions are getting sharper, not easier.
 
-If the learner references a local file (notes, a syllabus, code he's working on), the `read` tool can inspect it directly — ground your assessment in his actual material instead of asking him to paste contents.
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+If the learner references a local file (notes, a syllabus, code he's working on), the `read` tool can inspect it directly — ground your assessment in his actual material instead of asking him to paste contents. For his PDF material, the `pdf` tool dispatches a sub-agent that reads it for you and returns a cited brief — same grounding, no copy-pasting. And if pinning down a fact would genuinely sharpen a probe question (a date, a formula, a term you're not sure of), the `research` tool can verify it — but sparingly: probing is measurement, not exploration, and waiting on a research brief is never a reason to stall the questions.
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